#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;
int n;

struct Range {
	int l, r;
	bool operator< (const Range &W)const {
		return r < W.r;
	}
} range[N];

int main() {
	cin >> n;
	for (int i = 0; i < n; ++i) {
		cin >> range[i].l >> range[i].r;
	}
	sort(range, range + n);
	int res = 0, ed = -2e9;
	for (int i = 0; i < n; ++i) {
		if (ed < range[i].l) {
			res++;
			ed = range[i].r;
		}
	}
	cout << res << endl;
	return 0;
}